Air cleaner and silencer



Jan. 25, 1944. a. STEENSIEN 2,340,152

AIR CLEANER AND SILENCER Filed Nov. 4. 1940 !NVENTOR 38)?2474 52 884759);

fi M, Mill, Wm *M ATTORNEYfi- Patented Jenzs, 1944 2,340,152

UNITED STATES PATENT OFFICE AIR CLEANER AND SILENCER buretors in whichthe silencer comprises a closed vessel so arranged that oil cannot bepulled over from the oil bath into the silencer as in priorarrangements. The advantages of the present invention includecleanliness and the elimination Bernard Steensen, Detroit, Mich assignorto Chrysler Corporation, Highland Park, Mich, a corporation oi DelawareApplication November 4, 1940, Serial No. 364,113

2 Claims. (Cl. 183-15) The present invention relates to a device forof'a fire hazard since any oil which might be cleaning the air beingtaken into a carburetor, pulled over from the oil bath is drawn directlyparticularly of the downdraft type, and for silencinto the enginecylinders and burned. ing the noises emanating from the intake of an Afurther advantage of the present arrangeengine as well as produced bythe passage of thement over prior known arrangements. such as airthrough the cleaner and into the carburetor. horizontal in-linepositioning of the cleaner and It is an object of the present inventionto provide silencer, or other known prior arrangements, is I acarburetor air cleaner and silencer which 00- the elimination ofvibration breakage since the cupies a minimum height above thecarburetor only overhanging part is of light but rigid conwith which itis associated so as to reduce the 1 struction. v minimum under-hoodheight requirements. This An additional object of the invention is theobject is principally achieved by arranging the provision in an aircleaner and laterally oifset air cleaner vertically above the air intakeof the silencer assembly of a connecting throat between carburetor andarranging a silencer laterally of the cleaner and silencer portionswhich is so dithe body ofthe air cleaner instead of in line mensionallypredetermined with respect to the therewith as in prior practice. Theadvantages volume of the silencer as to serve as the attenuof such anarrangement include not only the reating means thereof, thus obviatingthe necessity duction of height of the carbiu'etor assembly but of aseparate and additional member for accomthe permission of largersilencers having greater plishing this purpose.

effect than those heretofore possible. A still further object of theinvention is the A further object 'of the present invention is toprovision in an air cleaner and silencer assembly provide an air cleanerand silencer comprising of this kind of a fire screen to preventigniting an open conduit leading directly into the intake of any fuelmixture which gains access to the tube of the carburetor and extendingcoaxially silencer under certain operating conditions of an 7 thereof soas to eliminate elbows and bends which engine. 7 tend to cause unequaldistribution of the air and These and other objects and advantages ofthe fuel mixture to the branches of the engine intake present inventionshould be more apparent from manifold. The advantages of the presentinven-p a study of the following specification taken in tion are:increased freedom of air travel due to connection with the accompanyingdrawing the elimination of the elbows and other restric- 'm wherein likenumerals refer to like parts through-. tions heretofore thoughtnecessary, improved disout. tribution of fuel mixture into the engineintake In the drawing, I manifold due to the straight flow of airconcen- Fig. 1 is a. viewin elevation of an internal comtrically intothe intake tube of the carburetor, bustion engine having the presentinvention apand improved carburetor performance due to the 3.", pliedthereto; concentric flow of air through the Venturi throat Fig. 2 is avertical section through the air of the carburetor. cleaning device andsilencer of the present in- A particular advantage resulting from thepresvention; ent invention is that the use of oil bath filtering Fig. 3is a fragmentary sectional view of a devices is greatly increased. Suchoil bath demodified form of the invention; vices require more verticalheight than dry filters The present invention is adapted to be assobutare far more efficient in removing dust and ciated with an internalcombustion engine Hi other foreign material fromthe air so that thecomprising intake manifold II and exhaust maniuse thereof is of greatadvantage. The present fold l2 and a downdraft carburetor l3 having aninvention permits the use of an oil bath filtering air intake tube Itincorporated therein. The air device in an automobile having under-hoodclear cleaner preferably comprises a stamped intake height arranged fora dry filter due to the offset chamber [5 which is divided into upperand lower lateral arrangement of the silencer. portions by an oil holderl6 adapted to hold a A further object of the present invention is tosupply of oil therein. The bottom wall of the inprovide a silenced,oil-bath air cleaner for carso take chamber I 5 is provided with aconcentric opening I! and protruding neck i8 adapted to be clamped ontothe top of the intake tube H by a clamping device I9.

The upper extremity of the wall of the intake chamber I5 is providedwith a. plurality of air collecting ports 20 located above the oilholder l8. and the wall terminates in an annular flange 2|. The intakechamber is adapted to be closed by a dome-shaped cover 22 having itsedge crlmped over and retaining a filter holding device comprising adepending flange portion 23 and upper and lower retaining grids 24 and25, respectively, suitably attached to the upper and lower edges of theflange portion 23. The grids of the intake chamber l5 by means of a bolt28 having a winged head 29, the lower end of which is threaded into amember 30 traversing the opening 1.

The tube 26 forms an open conduit concentrically aligned with the intaketube I, the lower end of the tube terminating centrally of the loweropen portion of the intake chamber I I so as to be spaced from the upperend of the intake tube H. The lower portion of the wall of the intakechamber I5 is provided with an opening 35 surrounded by a protrudingfiange 3B, and a silencer comprising a closed vessel 31 is associatedwith the intake chamber by welding neck I: thereon to the flange 36. Theflange 35 and neck 38 constitute a restricted connection generallydesignated by the numeral 38' between the interior of the silencer 31and the space surrounding the passage from the air cleaner through whichair is supplied to the engine. The silencer 21 is preferablycylindrical, and the neck 3| and fiange 3! are are also preferablycylindrical for ease of manufacturing and assembling. It may be seenthat the silencer comprises a very light shell of rigid constructionwhich maybe rigidly united to the air cleaningdevice and may be ofconsiderable size without requiring an increase in underhood freeheight. 7

Engine air intake silencers have heretofore been provided with anattenuating passage or passages which have for their sole purpose thefunction of eliminating the objectionable eifects of sounds having wavelength within predetermined limits which have been found to beparticularly disturbing. Such attenuating passages are so predeterminedin length and cross sectional dimensions with respect to the volume anddimensions of the silencer as to cause the sound wave reflected by thesilencer to occur in an out-of-phase relationship with respect to theoriginal sound waves emanating from the engine.

When the silencer is laterally offset as illus-' trated in the drawing,the restricted connection 38' between the silencer 31 and the spacesurrounding the passage from the air cleaner may be relied upon toprovide the attenuating passage. This connection 38' is accordingly sopredetermined in length and cross sectional dimensions with respect tothe volume of the silencer 31 as to cause the sound waves reflected bythe silencer to occur in an out-of-phase relationship with respect tothe original sound waves emanating from the engine the objectionableeffect of which it is desired to mitigate.

' While there has been devised,- and may be employed, mathematicalformulas for calculating the dimensions or attenuating passages of thischaracter, satisfactory results are, in actual practice, obtained bytrial and error methods. In the latter way, an air cleaner and silencerassembly may be accurately constructed to eliminate the objectionablesound waves emanating from an internal combustion engine ofpredetermined design and duplications of the assembly will serve for allengines of the same design. The restricted connection 38' thus servesthe dual function of communicatively connecting the silencer with theengine inlet air passage and attenuating sound waves of a selected rangethus obviating the requirement of an additional member to accomplish thelatter purpose.

The present invention, when in operation, causes air to pass through alabyrinth including the openings 20, the space between the fiangeportion 23 and the shell of the intake chamber, across the surface ofthe oil in holder l6 and through the interstices of the filteringmaterial 21, then into the upper end of the tube 28. The filteringmaterial 21 is impregnated or coated with oil which is carried from thesump It by the air stream which passes through the filter so as toincrease the filtering efiiciency of the device. Most of the heavyparticles of foreign matter, such as dust and grit will be trapped inthe oil held in the holder I8, and those finer particles which mightfiow across the surface of the oil and upward with the airstream will betrapped by the coated filtering material. A substantially equal quantityof air traveling at substantially the same velocity will fiow evenlyinto every equal segment of the intake tube 28, and the tube 28 is ofconsiderable length so that the air flow therethrough tends to befurther evenly distributed. The member an preferably comprises a centralenlarged portion, as shown in Fig. 2, and supporting arms of smalldiameter (not shown) so that the air flow into the intake tube It is notdisturbed thereby.

It may be seen that it would be impossible for oil, which might becarried from the oil holder I up through the filter and down the tube28, to

. become trapped in the silencer or vessel 31 since the particles of oilwould be carried directly into the carburetor and from there into thecylinders where they would be burned.

In order to prevent ignition of fuel mixture in the silencer andconsequent injury to the latter during back firing of the engine andotherunusual operating conditions thereof, a fire screen 40 offrusto-conical shape is disposed between the lower end opening of thetube 28 and the end opening of the intake tube It. This screen serves toprevent fiame propagation to the space surrounding the tube 26 as wellas to the interior of the silencer 31 without obstructing the free flowof air to the engine.

In the form of the invention illustrated in Fig. 3 of the drawings, theair cleaner and silencer assembly is substantially identical to thatshown in Figs. '1 and 2 with the exception that a fire screen 4| isprovided across the passage of the restricted connection 38'. Thisserves to prevent fiame propagation into the interior of the silencer l1and may be used alone or in combination with the screen 40 shown in Fig.2.

Having illustrated and described the preferred embodiments of myinvention, it should be apparent to those skilled in the art that thesame permits of modifications in arrangement and details. All suchmodifications as come within the scope of the followingclaimsareconsidered to be a part of my invention,

I claim:

1. An internal combustion engine air supplying system includingavertically extending substantially cylindrical casing comprising side,top and bottom walls, a horizontal partition in said casing between saidtop and bottom walls providing upper and lower chambers within saidcasing, said upper chamber having an atmospheric air inlet and includingmeans for cleaning the incoming air, a clean air conduit supported bysaid partition extending centrally within said casing and establishingcommunication between said upper and lower chambers, said conduitterminating short of the bottom wall of said casing, said bot- ,tom wallhaving a central opening providing an outlet for said lower chamber,said opening being axially aligned with said conduit, the space betweensaid bottom wall and the lower-extremity of said conduit accommodatinglateral flow of sound waves emanating from said engine into said lowerchamber, a silencer acoustically cooperating with said lower chambercomprising a casing having an end wall provided with an opening facing aside wall of said lower'chamber, said silencer casing having itslongitudinal axis extending horizontally from said lower chamber andincluding an impervious opposite end wall 'and impervious side walls,said lower chamber having an opening in its side wall registering withthe opening of said silencer end wall and having relationship withrespect to the original sound waves emanating from the engine.

, 2. An internal combustion engine air supply-- system including avertically extending substantially cylindrical casing comprising side,top and bottom walls, a horizontal partition in said casing between saidtop and bottom walls providing upper and lower chambers within saidcasing, said upper chamber having an atmospheric air inlet and includingmeans for cleaning the incoming air, a clean air conduit supported bysaid partition extending centrally within said casing and establishingcommuncaton between said upper and lower chambers, said conduitterminating short of the bottom wall of said casing, said bottom wallhaving a central opening providing an outlet for said lower chamber,said opening being axially aligned with said conduit,

the space between said bottom wall and the lower cooperating with saidlower chamber comprising a casing having an end wall provided with anopening facing a side wall of said lower chamber, said silencer casinghaving its longitudinal axis extending horizontally from said lowerchamber and including an impervious opposite end wall andimpervious sidewalls, said lower chamber having an opening in its side wall registeringwith the opening of said silencer end wall and having a substantialportion of its area horizontally aligned and in direct unobstructedsound wave communication with the space in said lower chamber betweensaid bottom wall of said casing and the lower extremity of said conduit,a sleeve rigid with and extending between said air cleaner and silencercasings and communicating with the registering openings thereof, saidsleeve having a sound attenuating passage therethrough so predeterminedin length and cross sectional area with respect to the volume of theinterior of said silencer casing as to cause the sound waves reflectedby the silencer to occur in out-of-phase relationship with respect'tothe original sound waves emanating from the engine, and a tubular firescreen concentric with said conduit and extending between the lower endof the latter and the bottom wall of said air cleaner casing forprotecting the interior of said air cleaner casing as well as saidsilencer.

BERNARD s'rEENsEN.

